P0855 moderate

Drive Switch Input Circuit High

The P0855 code means the vehicle's onboard diagnostic system has detected: Drive Switch Input Circuit High. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
moderate
Estimated cost
$100 - $500 (parts and labor)
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Common Symptoms

  • Check Engine Light illuminated
  • TCM incorrectly detects Drive when not selected
  • Gear indicator may show D at all times
  • Transmission shifting behavior may be unpredictable

Probable Causes (Ranked by Likelihood)

  • Open circuit in drive switch ground path Very High
  • Faulty range sensor stuck reading high in Drive High
  • Short to voltage in drive input signal wire Moderate
  • Disconnected range sensor connector Moderate

Step-by-Step Diagnostic Procedure

  1. Verify the range sensor connector is fully seated

  2. Check for an open ground at the sensor

  3. Test for short to battery voltage on the drive input wire

  4. Monitor live data through all gear positions to find the fault

Frequently Asked Questions

Is P0855 the opposite of P0854?

Yes. P0854 means the drive input is stuck low, while P0855 means it is stuck high. They indicate different types of electrical faults in the same circuit.

Can a disconnected connector cause P0855?

Yes, if the range sensor connector comes loose, the signal can float high due to the PCM reference voltage, making the TCM think Drive is always selected.

Is this a safety issue?

It can be. If the TCM thinks the vehicle is in Drive when it is actually in Park, it may cause unexpected behavior during starting or shifting.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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